In inkjet printing, an image is build up drop wise by jetting droplets of ink onto a receiving medium, using a print head. The image may cover the whole surface of the receiving medium. This is known as full bleed printing. In full bleed printing, an image is printed onto a receiving medium such that the image extends to the edges of a receiving medium. The image may extend to all edges of a receiving medium, or, for example in roll-to-roll printing, the image may extend to at least the side edges of the receiving medium. The area of the receiving medium not covered by droplets of ink should be as small as possible, resulting in white edges surrounding the image on the receiving medium being as small as possible.
In order to print full bleed, the droplets of the ink have to be positioned as close to the edge of the receiving medium as possible, in order not to leave white areas around the image. On the other hand, it is undesired to position droplets of ink outside the edges of the receiving medium, as, in that case, the ink applied outside the edges of the medium pollutes the printing apparatus. For example, the transport belt for transporting the receiving medium may be polluted, thereby polluting the backside of the receiving medium or polluting later receiving media. Thus, in order to print full bleed, it is preferred to print as close to the edges of the receiving medium as possible, however, without printing outside the side edges of the receiving medium.
Methods for full bleed printing are known, wherein the position of (side) edges of the receiving medium are monitored during printing, e.g. by scanning the receiving medium when printing. However, such a method may be inaccurate, e.g. because the scanner may be positioned inaccurately with respect to the print heads. For example due to differences in thermal expansion, the position of the scanner with respect to the print heads may vary, leading to inaccuracies in calibrating the position of the print heads with respect to the receiving medium during printing.
It is therefore an object of the present invention to provide a method for full bleed printing with improved accuracy. It is a further object of the present invention to provide an inkjet printing apparatus configured to carry out such method.